In some examples, a computer-readable medium includes instructions. The instructions may be executable by a processing resource to maintain a default roaming restrictions database that stores default roaming restriction attributes specific to roaming classes of service defined by a network operator. The default roaming restriction attributes may be specific to the roaming classes of service independent of mobile country code and mobile network code. The instructions may also be executable by the processing resource to perform a lookup into the default roaming restrictions database to identify a particular default roaming restriction attribute specific to a particular roaming class of service defined by the network operator.